-matt
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| posted on 20/11/12 at 02:39 PM |
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Best way to geta BEC moving?
Well since getting my R1 Indy road legal, my biggest problem has been starting without stalling!
I have now adjusted the clutch pedal, so there is a lot more feel, which has made things a lot better, but I'm struggling to get
"quick" launches.
The only way I'm getting consistent starts without stalling is by giving it a couple of revs, slowly release the clutch a bit, then once it
starts to roll, give it some more revs, and release the clutch fully.
I've tried giving it more revs (around 5k) and letting the clutch out quickly, but it just seems to stall.
So what is the usual way of getting a BEC moving quickly?
Cheers
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Benzo
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| posted on 20/11/12 at 02:41 PM |
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quote:
Originally posted by -matt
Well since getting my R1 Indy road legal, my biggest problem has been starting without stalling!
I have now adjusted the clutch pedal, so there is a lot more feel, which has made things a lot better, but I'm struggling to get
"quick" launches.
The only way I'm getting consistent starts without stalling is by giving it a couple of revs, slowly release the clutch a bit, then once it
starts to roll, give it some more revs, and release the clutch fully.
I've tried giving it more revs (around 5k) and letting the clutch out quickly, but it just seems to stall.
So what is the usual way of getting a BEC moving quickly?
Cheers
Dump it at 6-7k.. just make sure to take up the transmission slack 1st, everything is tight and you not on hot sticky slicks!
[Edited on 20/11/12 by Benzo]
[Edited on 20/11/12 by Benzo]
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ReMan
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| posted on 20/11/12 at 03:49 PM |
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"The only way I'm getting consistent starts without stalling is by giving it a couple of revs, slowly release the clutch a bit, then once
it starts to roll, give it some more revs, and release the clutch fully. "
Couple of revs is not enough, more reves but same technique :-)
www.plusnine.co.uk
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-matt
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| posted on 20/11/12 at 04:38 PM |
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ah ok, looks like more revs is it then 
im not quite used to this high revving thing yet, keep thinking I'm about to blow the bloody thing up 
Will have another play tomorrow, if i get 2 mins when it doesn't rain!
Cheers
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bi22le
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| posted on 20/11/12 at 04:59 PM |
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I was the same in my BEC. Easy for civilised starts but when doing fast start they need revs .
Think about it. In a normal car you would be sitting about about 2/3 of full revs or about 4nish.
BEC is the same. About 7k!!
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
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gaz_gaz
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| posted on 20/11/12 at 05:12 PM |
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Bring the revs up until you think "Jesus this cant be right" ,sidestep the clutch. And enjoy the ride
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eddie99
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| posted on 20/11/12 at 05:15 PM |
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Yep as above more revs, for a race start, its more like 10,000 when motor revs to 13k.
http://www.elitemotorsporteng.co.uk/
Twitter: @Elitemotoreng
Facebook: http://www.facebook.com/pages/Elite-Motorsport-Engineering/153409081394323
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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ian locostzx9rc2
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| posted on 20/11/12 at 06:01 PM |
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2000 to 3000 revs as sonn as it starts to bite off you go you can slip bike clutches quite alot never had a problem with my zx9r striker made my pedal
ratio approx 4 to 1 if that helps..
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jossey
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| posted on 20/11/12 at 08:50 PM |
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More beans my friend, more beans :-)
Then it won't stall but don't do it in the wet or wellllll you will find out like I did when I rented a bec.
Thanks
David Johnson
Building my tiger avon slowly but surely.
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lsdweb
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| posted on 20/11/12 at 10:14 PM |
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Rev limiter....
http://www.kewego.co.uk/video/iLyROoafYqXZ.html
But not in the wet ! http://www.kewego.co.uk/video/iLyROoaftKbj.html (Those are the Grand National jumps on the outside of the track and they are
huge!!
[Edited on 20/11/12 by lsdweb]
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Macbeast
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| posted on 22/11/12 at 06:51 PM |
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" Think about it. In a normal car you would be sitting about about 2/3 of full revs or about 4nish. "
You're kidding
2 K is ample. I bet Mr Clutch loves you
I'm addicted to brake fluid, but I can stop anytime.
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BenB
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| posted on 22/11/12 at 08:01 PM |
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On my ST1100 engined Locost the engine bogs a bit because the carbs take a while to adjust. So it was always 7k (out of the 8.5) and dump the clutch.
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xtimmyx
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| posted on 26/11/12 at 09:32 AM |
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In contrast to what pretty much everyone here is saying, in the beginning I actually found the easiest way to get going was to not touch the throttle
at all.
I found that the engine was way less prone to stalling when left on idle. Perhaps the engine's idle mode acts like an anti stall or something,
but I found that much easier than giving it 3-4k revs.
I still use that technique a lot as I find it the "safest" and most convenient way to get going without stalling, and can actually be done
in a somewhat reasonable pace. However after driving the car for 3.000 miles now I've become somewhat decent at making just plain starts with
3-4k revs as well, though they're way trickier.
Starting up hill though is still out of the question without reving 10k and dumping the clutch. 
The car is a MK Indy with a 2003 R1 5PW engine.
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40inches
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| posted on 26/11/12 at 12:41 PM |
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quote:
Originally posted by xtimmyx
In contrast to what pretty much everyone here is saying, in the beginning I actually found the easiest way to get going was to not touch the throttle
at all.
I found that the engine was way less prone to stalling when left on idle. Perhaps the engine's idle mode acts like an anti stall or something,
but I found that much easier than giving it 3-4k revs.
I still use that technique a lot as I find it the "safest" and most convenient way to get going without stalling, and can actually be done
in a somewhat reasonable pace. However after driving the car for 3.000 miles now I've become somewhat decent at making just plain starts with
3-4k revs as well, though they're way trickier.
Starting up hill though is still out of the question without reving 10k and dumping the clutch.
The car is a MK Indy with a 2003 R1 5PW engine.
I found this on the ZX9R, feed the clutch in at tick over, and the thing moves along nicely, 2-3000 rpm, and, stall
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umgrybab
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| posted on 26/11/12 at 12:57 PM |
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A bike engine doesn't have nearly as much torque as a car engine, having such a small flywheel amongst other things. Remember that power is
proportional to torque X rpm. As such, you need to give it a lot of revs to launch like most people are saying. I used to race FSAE cars which use a
bike engine and we used to launch anywhere from 6500 to 9000 depending on the setup of the car/engine.
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-matt
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| posted on 27/11/12 at 12:37 PM |
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Cheers all, I seem to have mastered this quite well now. About 4k revs and slowly release the clutch seems to work a treat.
I haven't done any 9k rev starts as mentioned, as the road has been so wet and damp, and I'm too scared as to how the car will react when
the rears start to spin from a standstill.
I scared the crap out of myself the other day going up a hill at about 40mph, in 3rd gear, gave it a bit of throttle, and the rear lost grip and
started drifting towards oncoming traffic for a few seconds, before it found traction.
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40inches
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| posted on 28/11/12 at 09:29 AM |
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quote:
Originally posted by -matt
Cheers all, I seem to have mastered this quite well now. About 4k revs and slowly release the clutch seems to work a treat.
I haven't done any 9k rev starts as mentioned, as the road has been so wet and damp, and I'm too scared as to how the car will react when
the rears start to spin from a standstill.
I scared the crap out of myself the other day going up a hill at about 40mph, in 3rd gear, gave it a bit of throttle, and the rear lost grip and
started drifting towards oncoming traffic for a few seconds, before it found traction.
What tyre pressures? should be between 14-18psi I would think.
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mcerd1
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| posted on 28/11/12 at 10:21 AM |
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quote:
Originally posted by Macbeast
" Think about it. In a normal car you would be sitting about about 2/3 of full revs or about 4nish. "
You're kidding
2 K is ample. I bet Mr Clutch loves you
^^^ thats what I was thinking...
or the other quiestion: 'whats your normal car ?'
mine's a 1.8 blacktop zetec and comes properly 'on cam' about 3.9k, I can only get away with 2.5 - 3k on a very grippy bit of dry
tarmac and it'd kill the clutch at that 
if I tried it at 4k even on a dry road I'd only spin the wheels and thats with my rubish clutch (should have got a an LUK one ) and decent
grippy tyres
-
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coyoteboy
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| posted on 28/11/12 at 01:03 PM |
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quote:
You're kidding 2 K is ample. I bet Mr Clutch loves you
He did say a fast start  My tin top redlines at 7300 and if I want a decent launch with boost I rev to about 4K, load up the clutch for a half a
second or so against the brakes and then sidestep but have to be careful as it tends to spin 3 of the 4 wheels if I do that, and snaps my neck. And
when the clutch is at 65K miles it's also the way I shattered a friction disc. A fast takeoff is usually 2K, slipping a bit then bring it up
fully as I push the throttle down fully.
On small bike engine'd cars I found you could easily pull off slowly at 2K but to get a decent launch needed 5K+ and a bit of slip or it just
bogs, but it's a wet clutch and deals with the abuse fairly nicely.
[Edited on 28/11/12 by coyoteboy]
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